It's the Same Old Song...

Butch Moore wrote on 8/3/2012, 11:31 AM

I plan to shoot a wedding event this weekend with a Panasonic AG-HMC80P. We've been doing most everything (corporate work) in 1080p, but haven't been thrilled with the down conversion from HD to DVD on video with lots of movement.

I'm considering an alternate format for the wedding. My choices on this camera are:

1080/60i, 1080/30p, 1080/24p, 720/60p, 720/30p, 720/24p, as well as DV 480/60i, DV 480/30P and DV 480/24P.

My target will be widescreen DVD.

I'm particularly confused on the differences in 720/60p and 720/30p. Tom Paunz spent much time a few months ago helping me with this, but for the life of me...it's now all a blur (kinda like cramming for a chemistry exam, the next week you don't remember much)!

My questions:

1. Which format "should" give me the best quality DVD?

2. What are other event videographers using and why?

Thanks

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Comments

Laurence wrote on 8/5/2012, 7:30 PM

If you are downrezzing from HD interlaced to SD interlaced, you need to choose an interlace method, but it doesn't matter which one. If you select no deinterlace method, Vegas will treat each frame like it is a progressive image and when it resizes, the interlace comb will alias and look terrible. If you choose a deinterlace method, vegas will separate the even and odd fields as it resizes and refold them back by alternating lines at the new size. Which method you choose in this instance is not important because it doesn't actually deinterlace. Now if you render into an SD progressive template, then the method will matter and it will be as Bob described. With an interlaced to interlaced resize, the only thing that is important is that a method is selected.

farss wrote on 8/6/2012, 7:49 AM

"I shoot with a Pany HMC150 and a search didn't turn up anything about line pair averaging in that cam. Yet, I wonder if line pair averaging could explain why I had less trouble with twitter when downrezing from 1080i to DVD, vs downrezing from 1080p30."

I've never seen "line pair averaging" mentioned in regard to a specific camera either. It's just part of how all cameras that shoot interlaced work...or should work. Oddly enough the first time I read about it was in a paper written by a Panasonic engineer. One source of confusion here could be that it is also referred to as "line pair Summation". There's a bit of an explaination here.

"Yet, I wonder if line pair averaging could explain why I had less trouble with twitter when downrezing from 1080i to DVD, vs downrezing from 1080p30."

Yes, because it reduces vertical resolution. The problem of twitter happens when a horizontal line or edge is thin enough to appear in only one field. By averaging or summing two fields no line can be small enough to only appear in one line. You see the same problem with scrolling text if the text has fine horizontal lines in the font.

"How can I measure or detect the number of vertical lines in my raw 1080i footage?"

The only way to measure resolution is by shooting a resolution chart and looking at it. There is other ways using software to analyse the image you've taken of a chart. . It all gets quite expensive very quickly if you really want to get into full on pixel peeping.

Bob.

TeetimeNC wrote on 8/6/2012, 8:48 AM

Bob, thanks for the additional explanation. It has seemed so counter intuitive to me that interlaced could exhibit less twitter than progressive, but your explanation helps me understand why that is so.

I notice in the HMC150 there is a vertical detail setting. I'm curious, is the purpose of this setting for reducing twitter?

/jerry